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Invention: Universal detector

By Justin Mullins

Zap a metal with light and the electrons on the surface ripple into waves – known as plasmons – which emit light of their own. The frequency of that light reflects the electronic nature of the surface and is highly sensitive to contamination.

Kevin Tetz and colleagues in the Ultrafast and Nanoscale Optics Group at the University of California, San Diego, have designed a system to exploit that to test for any surface contamination on the surface of, well, anything.

Their idea uses a thin layer of metal drilled with nanoscale holes, laid onto the surface being tested. When the perforated plate is zapped with laser light, the surface plasmons that form emit light with a frequency related to the materials touching the plate. A sensitive light detector is needed to measure the frequency of light given off.

The team says devices using this approach can be small and portable, will work on very low power, and could detect everything from explosives to bacteria. All that needs to be done now is build a system able to decode the light signatures.